Energy storage cell having a cylindrical housing and method of manufacture - Patents.com

Abstract

An energy storage cell (100, 300, 700) having a cylindrical, liquid-tight sealed housing having a first housing end face (140) and a second housing end face (150) and a housing shell (200) and a method for manufacturing the same are proposed. The cylindrical energy storage cell (100, 300) includes an electrode-separator assembly (104) disposed within the housing. The electrode-separator assembly (104) is in the form of a cylindrical winding formed of an electrode ribbon (105, 108) and at least one ribbon-like electrode-separator assembly (116, 117) having first and second terminal winding end faces (120, 130) and a winding shell. The electrode-separator assembly (104) is axially disposed within the housing such that the first winding end face (120) faces toward the first housing end face (140) and the second winding end face (130) faces toward the second housing end face (150). The energy storage cell is characterized in that the housing shell (200) of the energy storage cell is formed of spirally wound foil, preferably spirally wound metal foil, and includes at least two layers of foil, preferably metal foil.

Description

[Technical field]

[0001] The present invention relates to a cylindrical energy storage cell having an electrode-separator assembly in the form of a winding and a method for making the same. [Background technology]

[0002] Electrochemical energy storage elements are capable of converting stored chemical energy into electrical energy by oxidation-reduction reactions. The simplest form of electrochemical energy storage element is the electrochemical cell. It comprises a positive electrode and a negative electrode, between which a separator is placed. During discharge, electrons are released at the negative electrode as a result of an oxidation process. This gives rise to an electronic current that can be drawn by an external power consumer, where the electrochemical cell acts as an energy supplier. At the same time, an ionic current corresponding to the electrode reactions is generated in the cell. This ionic current crosses the separator and is made possible by the ion-conducting electrolyte. The separator thus prevents direct contact between the electrodes. But at the same time, it allows charge equalization between the electrodes.

[0003] If the discharge is reversible, i.e., it is possible to reverse the conversion of chemical energy to electrical energy during discharge and charge the cell again, it is said to be a secondary cell. The common designation of the negative electrode as the anode and the positive electrode as the cathode in a secondary cell refers to the discharge function of the electrochemical cell.

[0004] Secondary lithium-ion cells are used today as energy storage cells for many applications, since these cells can provide high currents and are characterized by a relatively high energy density. They are based on the use of lithium, which can be transferred back and forth in the form of ions between the electrodes of the cell. The negative and positive electrodes of lithium-ion cells are generally formed by so-called composite electrodes, which contain electrochemically inactive and electrochemically active components.

[0005] In principle, any material capable of absorbing and releasing lithium ions can be used as an electrochemically active component (active material) for secondary lithium-ion cells. For example, carbon-based particles such as graphitic carbon are used for the negative electrode. The active material for the positive electrode can be, for example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4) or derivatives thereof. The electrochemically active material is generally contained in the electrode in the form of particles.

[0006] As electrochemically inactive components, composite electrodes generally include flat and / or ribbon-shaped current collectors, e.g., metal foils, that act as carriers for the respective active materials. The current collector for the negative electrode (anode current collector) can be made, for example, of copper or nickel, and the current collector for the positive electrode (cathode current collector) can be made, for example, of aluminum. In addition, the electrodes can include electrode binders (e.g., polyvinylidene fluoride (PVDF) or another polymer, e.g., carboxymethyl cellulose), conductivity-enhancing additives, and other additives as electrochemically inactive components. The electrode binder ensures the mechanical stability of the electrode and in many cases also the adhesion of the active materials to the current collector.

[0007] As an electrolyte, lithium-ion cells typically contain a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (e.g., ethers and esters of carbonic acid).

[0008] When manufacturing lithium-ion cells, the composite electrode is generally combined with one or more separators to form an electrode-separator assembly. The electrodes and separators are often, but not necessarily, joined together, sometimes under pressure, by lamination or gluing. The assembly can then be impregnated with an electrolyte to establish basic functionality of the cell.

[0009] In many embodiments, the electrode-separator assembly is formed in the form of a winding or processed into a winding. In the first case, for example, the ribbon-shaped positive electrode and the ribbon-shaped negative electrode and at least one ribbon-shaped separator are separately fed into a winding machine and spirally wound into a winding having the arrangement: positive electrode / separator / negative electrode. In the second case, the ribbon-shaped positive electrode and the ribbon-shaped negative electrode and at least one ribbon-shaped separator are first combined, for example by applying pressure as described above, to form an electrode-separator assembly. In a further step, the assembly is then wound.

[0010] For applications in the automotive sector and other applications with high energy demands, such as in electric bicycles or tools, lithium-ion cells with the highest possible energy density are needed, which are also able to withstand high currents during charging and discharging.

[0011] Cells for the above mentioned applications are often designed as cylindrical round cells with a form factor of, for example, 21x70 (diameter*height in mm). This kind of cell necessarily includes an assembly in the form of a winding. Modern lithium-ion cells of this form factor can already achieve energy densities of up to 270Wh / kg.

[0012] WO 2017 / 215900 A1 describes an electrode-separator assembly and a cylindrical circular cell whose electrodes are ribbon-like and in the form of a winding. The electrodes each have a ribbon-like electrode that is loaded or coated with an electrode material. The electrodes of opposite polarity are arranged offset from each other in the electrode-separator assembly so that the longitudinal edge of the positive current collector protrudes from the winding on one side and the longitudinal edge of the negative current collector protrudes from the winding on the other side. For electrical contact of the current collectors, the cell has a sheet metal part that sits flat on the end face of the winding and is welded to the longitudinal edge of the current collector. This allows electrical contact with the current collectors and therefore also with the associated electrodes over their entire length. A cell with windings contacted in this way has a significantly reduced internal resistance. As a result, high current generation can be absorbed much better and also heat can be dissipated better from the winding.

[0013] Electrochemical energy storage cells generally have a metal housing. The housing of a cylindrical circular cell often includes a housing cup that serves as a receptacle for the wound electrode-separator assembly and a lid component that closes the opening of the housing cup. The housing cup can be a deep-drawn component made of, for example, aluminum or nickel-plated steel or stainless steel, with a wall thickness in the range of 0.1 mm to 2 mm.

[0014] A seal is usually arranged between the lid component and the housing cup, which on the one hand serves to seal the housing, but on the other hand also serves to electrically insulate the lid component and the housing cup from each other. The seal is usually attached on the edge of the lid component. To close the circular cell, for example, the opening edge of the housing cup can be bent radially inwards onto the edge of the lid component sealed by the seal (crimping process), so that the lid component including the seal is securely fixed in the opening of the housing cup.

[0015] Assembling the cell requires that the electrode-separator assembly first be fabricated in a separate work step before it is inserted into a cylindrical metal housing which is then sealed.

[0016] In the case of wound electrode-separator assemblies, the electrode windings themselves are first fabricated on a winding machine and then transported to a separate assembly line and inserted into the cup.

[0017] Another disadvantage of this procedure is that in order to insert the windings into the cup, a certain amount of free space or clearance must often be present between the outer diameter of the windings and the inner diameter of the cup. This free space remains unused in the assembled energy storage cell in terms of energy. The relatively high weight of conventional housing cups is also detrimental to the energy density of the cell. It can account for up to 15% of the total weight of the cell. Furthermore, conventional housing cups made of the above-mentioned metals are relatively expensive and, in the case of steel, are often prone to rust, especially in the area of ​​the cut edges caused by the manufacturing process. The system technology for feeding and inserting the windings into the cup is also complex and costly. Summary of the Invention [Problem to be solved by the invention]

[0018] Against this background, the present invention sets itself the task of providing an improved energy storage cell which allows optimal utilization of its volume, while at the same time simplifying the manufacturing process for the cell and thus allowing cost savings in the production of the cell. [Means for solving the problem]

[0019] This object is achieved by an energy storage cell having the features of claim 1. This object is further solved by a manufacturing method for such an energy storage cell according to the further independent claim 15. Advantageous embodiments of the energy storage cell are the subject matter of the dependent claims.

[0020] The energy storage cell according to the present invention has a cylindrical, liquid-tight sealed housing having a first housing end face and a second housing end face and a housing shell. The energy storage cell includes the following features: a. the cylindrical energy storage cell includes an electrode-separator assembly disposed within a housing; b. the electrode-separator assembly is in the form of a cylindrical winding formed of an electrode ribbon and at least one ribbon-like separator having first and second terminal winding end faces and a winding shell; c. the electrode-separator assembly is axially disposed within the housing such that the first winding end face faces toward the first housing end face and the second winding end face faces toward the second housing end face. Key aspects of the invention are the following features: d. The housing shell of the energy storage cell is formed of at least one spirally wound foil, preferably a spirally wound metal foil, and includes at least two layers of foil, preferably a metal foil.

[0021] The electrode ribbon preferably comprises a ribbon-shaped current collector and a coating of electrode material disposed thereon.

[0022] In particular, the energy storage cell according to the invention can be a cylindrical round cell. In another embodiment, it can also be a button cell. In this regard, the button cell differs from the cylindrical round cell in particular in that it is smaller and in the case of a button cell, the height of the cell is smaller than its diameter.

[0023] According to the concept according to the invention, the energy storage cell according to the invention dispenses with the conventional metal housing. Instead, the energy storage cell according to the invention is characterized by the fact that the housing shell of the cell is formed by a wound foil layer, in particular a metal foil layer. The foil, in particular the metal foil, is present in at least two layers. In other words, the housing shell is formed by at least two turns of foil, in particular metal foil.

[0024] Housing Shell Preferably, the housing shell comprises 2 to 50 layers of foil, particularly preferred is 2 to 25 layers, most preferred is 5 to 25 layers.

[0025] The foil, in particular the wound metal foil, preferably has a thickness in the range of 4 to 300 μm, preferably 4 to 100 μm, with a thickness of 4 to 50 μm, especially 4 to 25 μm being particularly preferred.

[0026] The number of layers for the housing shell can be adjusted depending on the thickness of the foil used. Thinner foils can provide more layers if necessary. The foil thickness and number of layers used will affect the strength and stability of the resulting housing shell. Additionally, the size or form factor of the energy storage cell can also play a role in the selection of foil thickness and number of layers. Smaller energy storage cells may require less material to achieve the required stability of the housing shell.

[0027] The design of the foil as a metal foil may be preferred for a number of reasons. For example, a housing shell made of metal foil usually has sufficient resistance to common liquid electrolytes, has high mechanical strength, and can act as a housing pole. In addition, a housing shell made of metal foil has the special advantage that the metallic material gives the housing shell significantly better heat dissipation properties.

[0028] However, in some embodiments, the foil used to form the housing shell can also be a plastic foil. The plastic foil is preferably free of pores that can be penetrated by the electrolyte and preferably has electrical insulating properties. Fiber-reinforced plastic foils may be particularly preferred. A housing shell formed of such a foil cannot serve as a housing pole. A pole bushing for contacting the electrode can be provided through the housing or the housing end face can be, for example, metallic and in electrical contact with the electrode. It is also possible to form one of the housing end faces of metal and contact one of the electrodes so as to electrically connect it to the other electrode, and provide a pole bushing for contacting the other electrode.

[0029] In other embodiments, it may be provided that the housing shell of the cell is formed of a different foil wound on a wound electrode-separator assembly, for example a multi-layer metal foil and a multi-layer plastic foil wound on the metal foil layer, or vice versa.

[0030] Advantages of the Invention The concept according to the invention, using the formation of the housing shell by means of a wound foil, in particular a wound metal foil, offers various significant advantages. In particular, the energy storage cell according to the invention does not require a separate metal housing cup into which the electrode-separator assembly must be inserted in a separate work step to form the housing, which would then need to be contacted, sealed and closed accordingly. Instead, the concept according to the invention makes it possible to carry out most of the assembly of the energy storage cell on a winding machine on which the electrode-separator assembly is already fabricated. Using the concept according to the invention, a separate assembly line for inserting the electrode-separator assembly and assembling the housing can therefore be dispensed with.

[0031] Another particular advantage of the concept according to the invention is that the internal space of the energy storage cell can be optimally utilized. The above-mentioned free space between the outer diameter of the winding and the inner diameter of the cup is not required. The housing shell is wound directly on the electrode-separator assembly and is only separated from it, possibly by a thin electrical insulating layer. There is no free space formed between the winding and the housing shell. This means that the internal volume of the cell can be optimally utilized for energy supply.

[0032] Avoiding a free space between the winding shell and the housing is also advantageous in terms of optimal cooling of the cell: in conventional cells, this free space, generally filled with air, can form a thermal insulating layer that makes it difficult to cool the cell.

[0033] A further particular advantage of the concept according to the invention is that any uneven winding diameters that may arise as a result of the coating process during the manufacture of the electrode ribbons can be optimally compensated for. For example, if the coating with electrode material is already somewhat uneven, the diameter of the winding will be slightly larger or smaller for a given length of wound electrode ribbon. Even small variations in diameter can already lead to problems during assembly and can lead to difficulties when inserting the electrode-separator assembly into the housing cup. This problem is also completely avoided with the concept according to the invention.

[0034] Furthermore, the concept according to the invention also offers significant cost savings: conventional deep-drawn housing cups are significantly more expensive than the foils, in particular metal foils, from which the housing shells according to the invention are formed.

[0035] Electrode-separator assembly First, an electrode-separator assembly is preferably fabricated in a manner known per se. Preferably, first, electrode ribbons, i.e. in particular electrode ribbons for the anode and electrode ribbons for the cathode, and at least one ribbon-shaped separator are provided for this purpose. In the electrode-separator assembly, the arrangement of these ribbons is, for example, as follows: first electrode ribbon (e.g., anode)-ribbon-shaped separator-second electrode ribbon (e.g., cathode)-ribbon-shaped separator. The ribbon-shaped anode, ribbon-shaped cathode and ribbon-shaped separator are spirally wound into the ribbon-shaped electrode-separator assembly.

[0036] To fabricate the electrode-separator assembly, the ribbon-shaped electrode together with at least one ribbon-shaped separator is preferably fed to a winding device, where it is preferably spirally wound around a winding axis, such as a winding mandrel.

[0037] In some embodiments, the electrodes and at least one separator are wound onto a cylindrical or hollow cylindrical winding core that remains in the winding body after winding for this purpose. For example, a first ribbon-shaped separator can be first bonded, for example glued or welded, to the winding core. Another ribbon-shaped separator between the electrode ribbons and the electrode ribbons is inserted and the winding process is started.

[0038] Alternatively, the windings may be formed, for example, on a winding mandrel which is again withdrawn from the windings after the windings have been formed.

[0039] Within the electrode-separator assembly, the individual ribbons are not necessarily securely joined or laminated to one another, but they are in contact, preferably pressed together.

[0040] It is also possible that a ribbon electrode-separator assembly is first formed with the ribbon electrodes having an arrangement of ribbon separators between the electrodes, and then the electrode-separator assembly is processed into a winding.

[0041] The winding shell can be formed, for example, by a plastic foil or an adhesive tape. It is also possible that the winding shell is formed by one or more turns of a ribbon-like separator.

[0042] In a particularly preferred embodiment, the electrode-separator assembly of the energy storage cell according to the invention is characterized by at least one of the following features a. to c: a. one of the electrode ribbons of the electrode-separator assembly is a positive electrode ribbon having a first longitudinal edge and a second longitudinal edge parallel thereto, the positive electrode ribbon including a ribbon-shaped cathode current collector coated on both sides with a positive electrode material; b. one of the electrode ribbons of the electrode-separator assembly is a negative electrode ribbon having a first longitudinal edge and a second longitudinal edge parallel thereto, the negative electrode ribbon including a ribbon-shaped cathode current collector coated on both sides with a negative electrode material; c. At least one ribbon separator electrically insulates the ribbon electrode strips of opposite polarity from each other.

[0043] Preferably, the above-mentioned features a. and b. and particularly preferably the above-mentioned features a., b. and c. are realised in combination.

[0044] Preferred Electrochemical Embodiments In a particularly preferred embodiment, the energy storage cell according to the invention may be a lithium-ion cell, whereby in principle all electrode materials known for lithium-ion cells, in particular all secondary lithium-ion cells, can be used for the electrodes or electrode ribbons of the energy storage cell.

[0045] In particular, carbon-based particles, such as graphitic carbon or non-graphitic carbon materials, also preferably in particulate form, having the ability to intercalate lithium may be used as the active material in the negative electrode. Alternatively or in addition, lithium titanate (Li4Ti5O 12) Or its derivative can also preferably be contained in the negative electrode in the form of particles. Further, as the active material, the negative electrode can optionally contain at least one material from the group including silicon, aluminum, tin, antimony, or a compound or alloy of these materials that can reversibly store and release lithium, such as silicon oxide (especially SiO x , where 0 < x < 2), in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The capacity for accepting lithium is many times greater than that of graphite or equivalent materials, especially in the case of silicon. A mixture of silicon and carbon-based storage materials is particularly suitable. A thin anode made of metallic lithium is also suitable.

[0046] Active materials suitable for the positive electrode include lithium metal oxide compounds such as LiCoO2 and LiFePO4, and lithium metal phosphate compounds. Lithium nickel manganese cobalt oxide (NMC) having the chemical formula LiNi x Mn y Co z O2 (where x + y + z is usually 1), lithium manganese spinel (LMO) having the chemical formula LiMn2O4, or lithium nickel cobalt aluminum oxide (NCA) having the chemical formula LiNi x Co y Al z O2 (where x + y + z is usually 1) is particularly suitable. Derivatives thereof, such as lithium nickel manganese cobalt aluminum oxide (NMCA) having the chemical formula Li 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 O2, or Li 1+x M - O compounds and / or mixtures of the aforementioned substances can also be used. The cathode active material is also preferably used in particulate form.

[0047] In addition, the electrodes of the energy storage cell according to the invention preferably contain an electrode binder and / or additives to improve electrical conductivity. The active material is preferably incorporated in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent has the function of increasing the electrical conductivity of the electrode. Suitable electrode binders are, for example, based on polyvinylidene fluoride (PVDF), lithium polyacrylate, styrene butadiene rubber or carboxymethyl cellulose or mixtures of different binders. Suitable conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0048] The energy storage cell according to the invention particularly preferably comprises an electrolyte, in the case of a lithium-ion cell, in particular an electrolyte based on at least one lithium salt, for example lithium hexafluorophosphate (LiPF6) present dissolved in an organic solvent (for example a mixture of organic carbonates or cyclic ethers or nitriles such as THF). Other lithium salts which may be used are, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(oxalato)borate (LiBOB).

[0049] Preferably, the layers of positive and negative electrode materials and the at least one ribbon separator are impregnated with an electrolyte.

[0050] At least one separator is preferably formed of an electrically insulating plastic foil. It preferably has pores so that it can be permeated by the liquid electrolyte. The plastic foil may consist, for example, of polyolefins or polyetherketones. Nonwovens and fabrics made of plastic materials or other electrically insulating fabrics may also be used as separators. Separators having a thickness in the range of 5 μm to 50 μm are preferred.

[0051] However, the ribbon separator can also be a separator made of a solid electrolyte that has inherent ionic conductivity and does not need to be impregnated with a liquid electrolyte. The solid electrolyte can be, for example, a polymer solid electrolyte based on a polymer conductive salt complex that exists in a single phase without a liquid component. The polymer matrix of the solid polymer electrolyte can be polyacrylic acid (PAA), polyethylene glycol (PEG) or polymethylmethacrylate (PMMA). Lithium conductive salts such as lithium bis-(trifluoromethane)sulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF6) and lithium tetrafluoroborate (LiBF4) can be present therein.

[0052] Nominal Capacity The nominal capacity of the lithium-ion based energy storage cell according to the invention, designed as a cylindrical round cell, is preferably at most 15000 mAh. With a 21x70 form factor, the energy storage cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1500 mAh to 7000 mAh, particularly preferably in the range of 3000 to 5500 mAh. With a 18x65 form factor, the cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1000 mAh to 5000 mAh, particularly preferably in the range of 2000 to 4000 mAh.

[0053] In the European Union, manufacturers' specifications for the nominal capacity of secondary energy storage cells are strictly regulated. For example, information on the nominal capacity of secondary nickel-cadmium cells must be based on measurements according to the IEC / EN 61951-1 and IEC / EN 60622 standards, information on the nominal capacity of secondary nickel-hydrogen cells must be based on measurements according to the IEC / EN 61951-2 standard, information on the nominal capacity of secondary lithium cells must be based on measurements according to the IEC / EN 61960 standard, and information on the nominal capacity of secondary lead-acid cells must be based on measurements according to the IEC / EN 61056-1 standard. Any information on nominal capacity in this application is preferably based on these standards.

[0054] Preferred Current Collector / Separator Embodiments The anode current collector ribbon, the cathode current collector ribbon and the at least one ribbon separator of the cell according to the invention preferably have the following dimensions: - Length in the range of 0.5m~25m, - Width in the range of 40mm~145mm.

[0055] The current collectors of the energy storage cell according to the invention have the function of making electrical contact over as large an area as possible with the electrochemically active components contained in the respective electrode materials, in particular the ribbon-shaped metal foils, which consist of a metal foil or are metallized at least on the surface.

[0056] In the case of the lithium-ion cell according to the invention, suitable metals for the anode current collector are, for example, copper or nickel or other conductive materials, in particular alloys of copper and nickel or metals coated with nickel. In particular, materials of type EN CW-004A or EN CW-008A with a copper content of at least 99.9% can be used as copper alloys. Alloys of type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable as nickel alloys. Stainless steels, for example types 1.4303 or 1.4404 or type SUS304, can also be considered.

[0057] For lithium-ion cells designed as energy storage cells according to the present invention, aluminum or other conductive materials including aluminum alloys are particularly suitable as metals for the cathode current collector.

[0058] Suitable aluminum alloys for the cathode current collector are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0059] Preferably, the anode current collector and / or the cathode current collector are each a ribbon-shaped metal foil having a thickness within the range of 4 μm to 30 μm.

[0060] Regarding the formation of the housing shell of the energy storage cell according to the invention by a spirally wound foil, two variants are particularly preferred: in the first of these variants, the housing shell is formed by one end section of the current collector contained in the electrode-separator assembly, in the second variant, the housing shell is formed by a separate metal foil.

[0061] Formation of the housing shell from the terminal collector sections According to a first variant, the energy storage cell according to the invention is characterized by at least one of the following additional features a. to c: a. the spirally wound foil forming the housing shell of the energy storage cell is a spirally wound end section of a ribbon-shaped cathode current collector that is not coated with cathode material; b. the spirally wound foil forming the housing shell of the energy storage cell is a spirally wound end section of a ribbon-shaped anode current collector that is not coated with anode material; c. The ribbon cathode current collector and the ribbon anode current collector have an essentially constant width along their entire length.

[0062] The above features a. and b. should be considered as alternatives, such that in this variant the housing shell is either formed by a metal foil that also forms the cathode current collector of the electrode-separator assembly, or is formed by a metal foil that also forms the anode current collector of the electrode-separator assembly.

[0063] Particularly preferably, the abovementioned features a. and c. or b. and c. are realised in combination with one another.

[0064] If the housing shell is formed by the non-coated cathode current collector ribbon, the structure of the electrode-separator assembly is preferably as follows: when viewed from the inside to the outside, the negative electrode ribbon, including the anode current collector ribbon, is terminated first. The coating on both sides of the cathode current collector is also terminated in this area. However, the metal foil ribbon forming the cathode current collector continues. The ribbon-like separator or separator group also continues, for example over two or three turns. Then, the ribbon-like separator or separator group also ends, leaving only the non-coated cathode current collector ribbon. The cathode current collector ribbon is then wound in several turns to form the housing shell.

[0065] If the housing shell is formed by the uncoated anode current collector ribbon, the structure of the electrode-separator assembly is preferably as follows: when viewed from the inside to the outside, the positive electrode ribbon including the cathode current collector ribbon is terminated first. Both the anode current collector and the coating are terminated in this area, but it continues with the ribbon-like separator for example over 2 or 3 turns. Then the ribbon-like separator is also terminated, leaving the uncoated anode current collector, which is wound in several turns to form the housing shell.

[0066] Formation of the housing shell from separate metal foils In a second preferred variant of the energy storage cell according to the invention, the housing shell is formed by a separate metal foil (shell metal foil). In this case, the energy storage cell according to the invention is characterized by at least one of the following additional features a. to d: a. the spiral wound foil forming the housing shell of the energy storage cell is a spiral wound metal foil ribbon wound onto the winding shell of the electrode-separator assembly; b. the winding shell of the electrode-separator assembly is made of an electrically insulating material; c. the metal foil ribbon has an essentially constant width along its entire length; d. The metal foil ribbon has a width greater than the ribbon cathode current collector and / or the ribbon anode current collector of the electrode-separator assembly.

[0067] In a particularly preferred embodiment, the above-mentioned features a. and b. or a. to c. or a. to d. are realized in combination with one another.

[0068] The electrical insulating material according to the above feature b. may in particular be at least one ribbon-shaped separator turn. Alternatively or additionally, after completion of the winding of the electrode-separator assembly or, if applicable, after the end of at least one ribbon-shaped separator electrode ribbon, a separate adhesive film or the like may be applied to the electrode-separator assembly to form a winding shell.

[0069] To simplify the formation of subsequent connections between the housing shell and the housing end faces, for example by welding, it may be advantageous if the metal foil ribbon for the housing shell has a larger width than the ribbon-shaped current collectors of the electrode-separator assembly.

[0070] However, the same metal ribbon used as the anode or cathode current collector can also be used as the metal foil ribbon, so that after winding the electrode ribbon, it is possible to cut the electrode ribbon, form a winding shell by subsequently winding at least one ribbon-like separator, and then insert the same metal ribbon used as the anode or cathode current collector in the anode or cathode between two turns of the separator, and then cut the separator so that only the metal ribbon is further wound.

[0071] Selection of materials for the housing shell In a particularly preferred embodiment of the energy storage cell according to the invention, the energy storage cell is characterized by one of the following features a. to c., relating to the material of the foil for the housing shell: a. the spirally wound metal foil forming the housing shell of the energy storage cell is made of aluminum or an aluminum alloy; b. the spirally wound metal foil forming the housing shell of the energy storage cell is made of copper or nickel or a copper or nickel alloy; c. The spirally wound foil forming the housing shell of the energy storage cell is made of plastic.

[0072] The above mentioned features a., b. and c. are generally to be understood as alternatives, but in principle it is also possible for the housing shell to be formed by several metal foils or metal and plastic foils of different materials.

[0073] The aluminum or aluminum alloy metal foil according to characteristic a. mentioned immediately above may preferably be an end section of the cathode current collector (according to the first preferred variant described above). The copper or nickel or copper or nickel alloy metal foil according to characteristic b. mentioned above may preferably be an end section of the anode current collector (according to the first preferred variant described above). In other embodiments, these metal foils (according to the second preferred variant described above) may be separate metal foils that are distinct from the current collector ribbon and may have a different width.

[0074] The use of aluminum or an aluminum alloy as the metal foil to form the housing shell may be particularly preferred because it is a more cost-effective material compared to copper or nickel.

[0075] However, the use of copper or nickel or copper or nickel alloys for the metal foil forming the housing shell can offer particular advantages, as these materials can generally be welded very well.

[0076] As mentioned above, in some embodiments, the at least one foil may also be a plastic foil. One suitable material for the foil would be polyetherketone.

[0077] In some particularly preferred embodiments, the spirally wound metal foil forming the housing shell can also be covered with a plastic cover for mechanical stabilization and / or to seal the housing. This plastic cover can be formed, for example, of a molded plastic part or two or more preformed molded plastic parts joined together by welding or gluing. Another option is to cover the shell and, optionally, at least a part of the housing end faces with liquid plastic or a liquid plastic precursor, for example by overmolding in a suitable injection mold.

[0078] adhesive layer In particularly preferred embodiments, the energy storage cell according to the invention is characterized by the following additional features: a. The layers formed of at least one foil, in particular a metal foil, which form the housing shell of the energy storage cell are connected to one another by adhesive layers arranged between the foil, in particular the metal foil, layers.

[0079] Adhesive bonding of the layers of the housing shell can be particularly advantageous, as this can improve the robustness of the housing. Standard liquid or hot melt adhesives or similar can be used for this purpose. For example, a thermoplastic that is then heat cured can be used. Suitable plastics, for example based on polyurethane or similar, can also be encapsulated.

[0080] Adhesive tapes which are capable of forming an adhesive bond on both sides to a layer of foil, in particular a metal foil, can also be used as adhesive layers. Adhesive tapes which are coated on both sides with adhesive or tapes which have inherent adhesive properties are suitable for this purpose.

[0081] In a preferred embodiment, such an adhesive layer can be sprayed or squeegee'd onto at least one foil before it is rolled up. For example, the last few centimeters of the current collector that are not coated in this section and are intended to form the housing shell can be pre-coated with a thermoplastic material.

[0082] Housing end face design In a particularly preferred embodiment of the energy storage cell according to the invention, the cell is characterized by at least one of the following additional features a. to d: a. the first housing end of the energy storage cell is formed by a round, particularly circular, metal disk or a metal cap including a round, particularly circular, base and a peripheral side wall; b. the metal disk or cap forming the first housing end face is connected to the housing shell by welding; c. the second end surface of the housing of the energy storage cell is formed by a round, particularly circular, metal disk or a metal cap including a round, particularly circular, base and a peripheral side wall; d. The metal disk or cap forming the second end surface of the housing is connected to the housing shell by welding.

[0083] In a preferred embodiment, the above-mentioned features a. and b or the above-mentioned features c. and d. are realized in combination with one another. In principle, the end faces of the housing can both be formed by round metal disks or metal caps, and thus the above-mentioned features a. and c. or particularly preferably the above-mentioned features a. to d. are realized in combination with one another.

[0084] The peripheral sidewall of the cap is preferably an inwardly projecting collar of the cap. Preferably, the sidewall is at an angle of approximately 90° to the circular base. This peripheral sidewall may facilitate assembly and joining of the individual elements of the energy storage cell of the present invention and connection of the housing shell to the end faces of the housing.

[0085] The round shape of the metal disk or the round shape of the bottom of the cap is characterized in that the shape has no corners and can therefore be easily integrated into the winding process. A circular shape is particularly preferred as it therefore fits particularly well with a uniformly wound electrode-separator assembly with a circular base.

[0086] Polar bushing through the housing end face In a further preferred embodiment of the energy storage cell according to the invention, the cell is characterized by at least one of the following additional features a. and b: a. Electrical contact electrodes electrically insulated from each housing end face and electrically connected to one of the ribbon-shaped current collectors directly or via a metal conductor are led through the first housing end face and / or the second housing end face; b. One of the ribbon-shaped current collectors is electrically connected directly or via a metal conductor to the metal disk or cap forming the first end surface of the housing or to the metal disk or cap forming the second end surface of the housing.

[0087] In some preferred embodiments, the above-mentioned features a. and b. are realised in combination with each other, and one of the poles of the energy storage cell, e.g. the negative pole, is formed by a contact pole protruding from one end face of the housing, and the other pole of the energy storage cell, e.g. the positive pole, is formed by the opposite end face of the housing.

[0088] The contact pole guided through one of the end faces can be a hollow bolt, for example through a cavity in the bolt a weld can be performed so that the bolt can be connected to the underlying component. The opening of the bolt can then be closed. The bolt itself is advantageously electrically insulated from the rest of the housing end face, for example by a plastic, ceramic or glass seal. For the assembly of the energy storage cells, it is particularly advantageous if the caps or disks forming the respective end faces of the energy storage cells form pre-assembled closure components with insulated bolts that can be assembled in this way.

[0089] Direct connection of the current collector to the end face of the housing In a particularly preferred embodiment of the energy storage cell according to the invention, the cell is characterized by at least one of the following additional features a. to c: a. a ribbon-shaped anode current collector including a main area loaded with a layer of negative electrode material and a free edge strip extending along a first longitudinal edge thereof that is not loaded with negative electrode material; b. the ribbon-shaped cathode current collector includes a main area loaded with a layer of positive electrode material and a free edge strip extending along a first longitudinal edge thereof that is not loaded with positive electrode material; c. The electrode ribbon is - a first longitudinal edge of the anode current collector or a first longitudinal edge of the cathode current collector protrudes beyond one of the end winding end faces; or - a first longitudinal edge of the cathode current collector projects from one end winding end face of the electrode-separator assembly, and a first longitudinal edge of the anode current collector projects from the other end winding end face. In order to achieve this, the electrode-separator assembly is arranged as a wound body.

[0090] Preferably, the above-mentioned features a. and c. or b. and c. or particularly preferably a., b. and c. are realised in combination with one another.

[0091] In the above-described embodiments in which the ribbon-shaped current collector is directly connected to a metal disk or cap forming the first housing end face or to a metal disk or cap forming the second housing end face, the first longitudinal edge of the anode current collector or the first longitudinal edge of the cathode current collector protruding from one of the end winding end faces is particularly preferably directly connected to the metal disk or cap, preferably by welding.

[0092] The edge strips of the current collector protruding from the respective winding end faces and free from electrode material allow particularly advantageous contacting of the electrodes according to the following particularly preferred features: a. One of the ribbon-shaped current collectors is directly connected to the metal disk or cap forming the first end face of the housing or to the metal disk or cap forming the second end face of the housing, and a first longitudinal edge or free edge strip of each current collector rests directly on the bottom of the metal disk or cap and is connected to the bottom of the disk or cap by welding, preferably over its entire length.

[0093] This form of direct contact of the current collectors via their longitudinal edges allows the electrodes to be contacted over their entire length. Cells having such contact of the electrodes are characterized by a significantly reduced internal resistance, which allows high currents to be captured much better than with conventional contact of the electrodes, and also allows heat to be better dissipated from the windings.

[0094] In some preferred embodiments, contact of this kind is provided only for the anode or only for the cathode, preferably only for the cathode, whereby to the other electrode, in particular the anode, contact may be provided, for example via a contact strip or the like, as described below.

[0095] Electrical connection of the current collector via at least one contact strip In further preferred embodiments of the energy storage cell according to the invention, at least one of the following additional features a. and b. is provided: a. at least one of the ribbon-shaped current collectors has at least one free section that is not coated with electrode material and to which a metal contact strip is welded; b. A metal contact strip welded to the current collector shall protrude from one of the winding end faces.

[0096] Preferably, the above mentioned features a. and b. are realised in combination with each other.

[0097] The metallic contact strips, which may also be called arrestor strips, allow the electrodes to be contacted very easily. Preferably, the metallic contact strips are perpendicular to the winding or running direction of the electrode ribbon or ribbon-like current collector.

[0098] Such contacting of one of the electrode ribbons via a contact strip may be combined with other contacting options: it may be provided that one of the electrodes is contacted via a contact strip and the other electrode is contacted in another way, for example via a direct connection of one longitudinal edge of the spirally wound electrode ribbon to the end plate metal sheet.

[0099] The contact strips are preferably made of the same material as the respective current collectors: for example, contact strips made of copper or a copper alloy are suitable as contact strips for the anode, and contact strips made of aluminum or an aluminum alloy are suitable as contact strips for the cathode.

[0100] In a particularly preferred further development of this aspect of the invention, the energy storage cell is characterized by the following additional feature a: a. The metal contact strip welded to the current collector is preferably connected directly by welding to the metal disk or cap forming the first end face of the housing or to the metal disk or cap forming the second end face of the housing.

[0101] Preferably, only one of the current collectors is thus connected to the first or second housing end face via a metallic contact strip. The current collectors of electrodes with opposite polarity are preferably contacted in a different manner.

[0102] In the above-mentioned embodiments in which the ribbon-shaped current collector is connected via an electrical conductor to a metal disk or cap forming the first end face of the housing or to a metal disk or cap forming the second end face of the housing, the electrical conductor is particularly preferably a contact strip, which may be welded directly to the metal disk or cap.

[0103] The winding end face from which one of the longitudinal edges of the contact strip or current collector protrudes is formed by at least one longitudinal edge of at least one ribbon-shaped separator protruding slightly beyond the coating of the electrode ribbon on the end face of the winding.

[0104] Target deformation of the longitudinal edges of the current collector In a particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the following additional features a. and b: a. a first longitudinal edge of the anode current collector and / or a first longitudinal edge of the cathode current collector protrudes from one of the end winding end faces and has a spiral shape; b. At least the outer turn of the first longitudinal edge is bent toward or away from the central axis of the electrode-separator assembly.

[0105] Preferably, the above mentioned features a. and b. are realised in combination with each other.

[0106] When assembling an energy storage cell according to the invention, it is particularly advantageous to bend the first longitudinal edge of the current collector protruding from one or both winding end faces, since in this way the caps or disks on the end faces can be very well and efficiently bonded to the respective winding end faces.

[0107] metal contact elements In particularly preferred embodiments of the energy storage cell according to the invention, the cell is characterized by at least one of the following additional features a. to e: a. the energy storage cell comprises at least one metallic contact element, optionally including a separate electrical conductor fixed to the contact element, connected by welding, in some preferred embodiments over its entire length, to a first longitudinal edge of the cathode current collector or the anode current collector, via which said current collector is electrically connected to a metallic disk or cap forming the first housing end face or a metallic disk or cap forming the second housing end face; b. the contact element seats flat on the first longitudinal edge of the cathode current collector or the anode current collector; c. the contact elements include a first element seated flat on a first longitudinal edge of the current collector projecting from the first or second end face and extending parallel to the respective winding end face, and a second element adjacent to the first element at an angle through which the first element is electrically connected to a metal disk or cap forming the first housing end face or a metal disk or cap forming the second housing end face; d. the contact element is connected directly, in particular by welding, to a metal disk or cap forming the first housing end face or to a metal disk or cap forming the second housing end face; e. The contact element makes contact directly or via an electrical conductor with an electrical contact pole passing through the first housing end face and / or the second housing end face.

[0108] In particularly preferred embodiments, the above-mentioned features a. and b., or a., b. and c., or a., b., c. and d., or features a. to e. are realised in combination with one another.

[0109] It is particularly preferred if such a contact element rests on a first longitudinal edge of the anode current collector.

[0110] The contact element is preferably a sheet metal component, for example in the form of a cap or disk or in the form of a strip. The sheet metal component preferably has a thickness in the range of 0.05 to 1.0 mm.

[0111] The contact element can also be a star-shaped sheet metal component.

[0112] Preferably, the energy storage cell comprises an insulating element which electrically insulates the contact element from the metal disk or cap forming the end face of the housing by preventing direct contact between the contact element and the metal disk or cap. In this embodiment, contact poles according to feature e. above, in which the electrical contact is routed to the outside, are particularly preferred. The contact poles, for example conventional contact bolts, are in contact with the contact elements which are thus in electrical contact with the respective electrodes.

[0113] This realization of electrical contact with the contact electrodes may be provided in particular for the anode side, while feature d. above may, for example, be provided for the cathode side of the energy storage cell.

[0114] Alternatively, in a preferred embodiment, the contact element can be omitted on the cathode side, for example, whereby the housing end face on the cathode side is formed, for example, by a metal disk or metal cap which is in direct contact with the free edge strip of the cathode current collector emerging from this side of the winding. Alternatively, the electrical connection can also be made via a metal contact strip as described above.

[0115] There are two preferred variants (variant A and variant B) for electrically assembling the contact elements, which are preferably connected by welding to the first longitudinal edge or free edge strip of the current collector protruding from the first end winding end face, to a metal disk or metal cap, respectively also referred to as a cover component, forming the housing end face.

[0116] According to variant A, the cell according to the invention is characterized by at least one of the following characteristics a. to c.: The contact element is directly connected to the cover component. b. the contact element includes a first element or section that seats flat on a first longitudinal edge of the current collector that protrudes from the end winding end face and extends parallel to the winding end face. c. the contact element includes a second element or section that is angled relative to the first section, through which the first section is electrically connected to the cover component.

[0117] The immediately preceding features a and b are preferably realized in combination. The immediately preceding features a to c are particularly preferably realized in combination.

[0118] According to variant B, the cell according to the invention is characterized by at least one of the following characteristics a. and b.: a. The contact elements are connected to the cover component via separate electrical conductors. b. The contact element seats flat on a first longitudinal edge of the current collector that protrudes from the end winding end.

[0119] The immediately preceding features a. and b. are preferably implemented in combination.

[0120] If a separate electrical conductor is used, it is preferably made of the same material as the contact element itself.

[0121] Of course, it is not only the first longitudinal edge of the current collector protruding from one end winding end that needs to be electrically contacted. Conversely, the first longitudinal edge of the current collector protruding from the other end winding end face must also be electrically contacted. According to the invention, the following two variants C and D are preferred.

[0122] According to variant C, the cell according to the invention is characterized by the immediately following feature a.: a. A first longitudinal edge of the current collector protruding from the other end winding end face seats directly on the metal disk or cap forming this housing end face and is connected thereto by welding.

[0123] According to variant D, the cell according to the invention is characterized by the immediately following feature b.: b. the energy storage cell includes a contact element connected by welding to a first longitudinal edge of a current collector protruding from the other end winding end face, through which contact element the current collector is electrically connected to a metal disk or metal cap forming the housing end face.

[0124] In either case, the longitudinal edge of the current collector protruding from the other end winding end may be electrically and / or thermally connected along its entire length as in the case of the current collector protruding from the opposite end winding end.

[0125] The energy storage cell according to the invention is particularly preferably characterized by the following feature a: a. the current collector protruding from the first end winding end face is an anode current collector, and the current collector protruding from the second end winding end face is a cathode current collector.

[0126] This configuration is particularly advantageous when the foil forming the housing shell consists of aluminum or an aluminum-containing alloy, since the cathode current collector is also preferably made of aluminum.

[0127] In a particularly preferred further development of the invention, the contact element electrically connected to the anode current collector is characterized by at least one of the immediately following features a. and b.: a. The contact elements shall consist of nickel, copper, or titanium or a nickel, copper, or titanium alloy or stainless steel, e.g. type 1.4303 or 1.4404 or type SUS304, or nickel-plated copper. b. The contact element is made of the same material as the anode current collector.

[0128] The immediately preceding features a. and b. are preferably implemented in combination.

[0129] Copper is an especially preferred material for the contact element which is connected to the anode current collector.

[0130] In embodiments in which the cathode current collector is also electrically connected via a contact element, this contact element is characterized by at least one of features a. and b. immediately below: The contact elements shall be made of aluminum or an aluminum alloy. b. The contact element is made of the same material as the cathode current collector.

[0131] The immediately preceding features a. and b. are preferably implemented in combination.

[0132] Aluminum is an especially preferred material for the contact element which is connected to the cathode current collector.

[0133] Contact elements which can be used according to the invention for contacting the longitudinal edges of the current collector are particularly preferably characterized by at least one of the following characteristics a. to g: They preferably have a uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm. b. They have two opposite planar faces and extend essentially in only one dimension. c. They are designed as or contain discs or polygonal plates or stars. d. They are dimensioned to cover at least 40%, preferably at least 60%, particularly preferably at least 70% of the first end winding end surface and / or the second end winding end surface. e. They have at least one aperture, in particular at least one hole and / or at least one slot. f. They have at least one bead formed as an elongated depression on one flat surface of the contact element and an elongated ridge on the opposing flat surface, the flat surface having the elongated ridge resting on a first longitudinal edge of the respective current collector. g. that they are welded to the first longitudinal edge of the respective current collector in the region of the bead via one or more weld seams located in particular within the bead.

[0134] It is particularly preferred that the immediately preceding features a, b and d are realized in combination with one another. In a preferred embodiment, features a, b and d are realized in combination with one of features c or e or features f and g. It is particularly preferred that all features a to g are realized in combination with one another.

[0135] Covering the winding end faces as extensively as possible is important for the thermal management of the energy storage cell according to the invention. The greater the coverage, the easier it is to contact the first longitudinal edge of each current collector over its entire length, if possible. Thus, the heat generated in the electrode-separator assembly can be better dissipated through the contact elements.

[0136] Pretreatment of the current collector In some embodiments, it has been found to be advantageous to subject the longitudinal edge of the current collector to a pretreatment before the contact element is placed thereon. In particular, at least one recess corresponding to at least one bead or elongated ridge on the corresponding flat surface of the contact element can be folded into the longitudinal edge. This also applies with regard to the bonding of a metal disk or cap forming the housing end face and which may be in direct contact with the respective winding end face. This metal disk or cap may also be provided with one or more beads which may facilitate contact with the edge of the current collector.

[0137] The longitudinal edges of the current collectors may also be oriented by pretreatment, for example they may be bent in a predefined direction, in particular towards the central axis of the electrode-separator assembly, as already explained above in connection with the contact with the metal disk or cap.

[0138] At least one aperture in the contact element may be particularly advantageously used to impregnate the electrode-separator assembly with electrolyte during assembly of the energy storage cell, which aperture may then be closed, for example by means of a blind rivet.

[0139] A combination of desirable features In a particularly preferred embodiment of the energy storage cell according to the invention, the cell is characterized by at least one of the following features a. to f., preferably by a combination of the following features a. to f.: a. the spirally wound foil forming the housing shell of the energy storage cell is a spirally wound end section of a ribbon-shaped cathode current collector that is not coated with a positive electrode material or a spirally wound end section of a ribbon-shaped cathode current collector that is not coated with a positive electrode material; b. the first housing end of the energy storage cell is formed by a metal cap including a rounded, particularly circular, base and a peripheral side wall, the metal cap having an opening edge that bounds the peripheral side wall; c. the opening edge of the cap forming the first housing end surface is connected to the housing shell by welding; d. the second housing end of the energy storage cell is formed by a metal cap including a rounded, in particular circular, bottom and a peripheral side wall; e. the spirally wound foil extends from the outside against a side wall of the cap forming the second end surface of the housing; f. the spirally wound foil is connected to a side wall of the cap forming the second end surface of the housing by a circumferential weld seam.

[0140] Therefore, this embodiment of the energy storage cell according to the invention according to the above features a. to f. is characterized in particular by the fact that the housing shell is formed by one end section of a current collector wound around the electrode-separator assembly, preferably this is a cathode current collector made of aluminium or an aluminium alloy.

[0141] Preferably, a first end surface of the housing forms the negative, or anode, side of the cell and a second end surface of the housing forms the positive, or cathode, side of the cell.

[0142] Particularly advantageously, in addition to the above-mentioned features a. to f., it can be provided that the first end face of the housing also comprises a contact element. This contact element is preferably in direct electrical contact with the free edge area of ​​the anode current collector protruding on this side of the winding. Preferably, the contact element is also electrically insulated from the cap forming this first end face of the housing. In addition, preferably, an electrical contact, i.e. a pole bushing, which leads the negative electrode to the outside on this end face of the cell, is provided on this end face of the housing.

[0143] In another preferred embodiment of the energy storage cell according to the invention, the cell is characterized by at least one of the following features a. to f., preferably a combination of these following features a. to f. is provided: a. the spiral wound foil forming the housing shell of the energy storage cell is a spiral wound foil ribbon, in particular a metal foil ribbon, wound onto the winding shell of the electrode-separator assembly; b. the first housing end surface of the energy storage cell is formed by a metal disk having a boundary edge; c. a boundary edge of the disk forming the first housing end surface is connected to the housing shell by welding; d. the second housing end of the energy storage cell is formed by a metal cap including a rounded, in particular circular, bottom and a peripheral side wall; e. the spirally wound foil extends from the outside against a side wall of the cap forming the second end surface of the housing; f. the spirally wound foil is connected to a side wall of the cap forming the second end surface of the housing by a circumferential weld seam.

[0144] In contrast to the previous embodiment, the energy storage cell according to this preferred embodiment is characterized by the fact that there is no current collector forming the housing shell, but a separate foil ribbon, in particular a metal foil ribbon, wound on the winding shell of the electrode-separator assembly is provided for this purpose. This foil ribbon may have a width somewhat larger than the electrode ribbon and the ribbon-like electrode-separator assembly, so that the wound housing shell has a greater height than the winding. In particular, in the region of the first housing end face, the housing end face may be designed accordingly, in that a metal disk is provided instead of a metal cap. This is a particularly advantageous way of achieving a flush finish on the first end face of the housing. Furthermore, this embodiment of the energy storage cell may be designed similarly to the embodiment of the energy storage cell described above.

[0145] It may also be preferred that the foil ribbon, especially the metal foil ribbon, be thicker than the electrode ribbon current collector, so that fewer turns are required to form the housing shell.

[0146] In a preferred embodiment of the energy storage cell according to the invention, an insulating element is advantageously provided within at least one of the end faces of the cell, in particular, the insulating element may electrically insulate a metal disk or cap forming the first end face of the housing from the contact elements provided in this area and from the upper area of ​​the windings in this area of ​​the cell.

[0147] Insulation elements The insulating element can be realized as follows, in a first embodiment, the energy storage cell according to the invention is characterized by at least one of the following features a. to c: a. At least one insulating element is or includes an insulating tape applied to an edge delimiting the winding end face and protecting it from direct contact with the housing end face and / or the interior of the housing shell. b. at least one insulating element is or includes an annular molded part made of plastic, preferably with an L-shaped cross section, applied to the edge delimiting the winding end face and protecting it from direct contact with the housing end face and / or the interior of the housing shell. c. The insulating tape or annular molded plastic part has a thickness within the range of 10 μm to 200 μm.

[0148] The immediately preceding features a. and c. or b. and c. are preferably realised in combination with one another.

[0149] The insulating tape can be, for example, a Kapton / polyimide adhesive tape.

[0150] Preferably, an annular molded plastic part with an L-shaped cross section can be, for example, injection molded and pressed onto the edge to be protected. It can, for example, consist of Teflon or polyamide.

[0151] In a further preferred embodiment of this aspect of the invention, the energy storage cell according to the invention is characterized by at least one of the features a. and b. immediately below: a. At least one insulating element is or includes an electrically insulating plastic coating that seals the edges of the contact elements. b. The electrically insulating coating is formed by overmolding the edges of the contact elements.

[0152] The immediately preceding features a. and b. are preferably implemented in combination.

[0153] Basically, all thermoplastic materials having electrically insulating properties are suitable for overmolding the edges of the contact elements, for example polyamides.

[0154] If desired, a combination of these embodiments of the insulating element can also be provided, whereby an insulating tape or an annular moulded part made of plastic is implemented in addition to a plastic coating on the edge of the contact element.

[0155] In particularly preferred embodiments, the energy storage cell according to the invention is characterized by at least one of the following additional features: a. the metal cap forming at least one of the end faces of the housing has in its edge region a peripheral recess, in particular an annular recess, bounded on the outside by a peripheral side wall of the metal cap; b. The peripheral side wall of the metal cap lies flat against the foil forming the housing shell.

[0156] Preferably, the above mentioned features a. and b. are realised in combination with each other.

[0157] A particular advantage of this embodiment lies, inter alia, in the fact that the peripheral recess in the metal cap offers a particularly good engagement option for welding the foil forming the housing shell to the end face of the housing, i.e. to the metal cap. This recess makes it possible, for example, to apply the laser beam in a particularly favorable manner so that it first penetrates the (generally thicker) side wall of the metal cap before it hits the foil layer of the housing shell in order to weld the housing shell to the cap. This has been found to create a very stable connection between the housing shell and the end face of the housing. In particular, the laser beam can be applied so that it penetrates all the foil layers of the housing shell from the inside to the outside.

[0158] In particular, the recess itself may be designed as an annular gap or groove and may be produced, for example, in a deep-drawing process. Preferably, it has a triangular cross section.

[0159] The method according to the present invention The present invention further includes a method of manufacturing an energy storage cell having a cylindrical, liquid-tight sealed housing having a first housing end face and a second housing end face and a housing shell as described above, the method including the steps of: a. an electrode-separator assembly in the form of a winding having two terminal winding end faces and a winding shell is produced on a winding machine, the electrode-separator assembly being formed, in particular wound, from electrode ribbons, between which at least one ribbon-shaped electrode-separator is arranged, the electrode ribbons each comprising a ribbon-shaped electrode, preferably coated with an electrode material; b. A housing shell is formed by winding a foil, in particular a metal foil.

[0160] The housing shell of the energy storage cell is particularly preferably formed by spirally winding a foil, in particular a metal foil, around the electrode-separator assembly, in particular such that it comprises at least two layers of foil, in particular a metal foil.

[0161] The current collector is preferably coated on both sides with the electrode material.

[0162] The electrode-separator assembly is preferably manufactured in a conventional manner on a winding machine. A crucial difference with conventional manufacturing processes for energy storage cells with wound electrode-separator assemblies lies in the formation of the housing shell. According to the invention, the housing shell is formed by winding at least two layers of foil, in particular metal foil, onto the winding shell of the electrode-separator assembly. The attendant advantages, firstly with regard to optimal utilization of the internal volume of the energy storage cell and secondly, especially in the significantly simplified manufacturing process, have already been explained in connection with the energy storage cell itself. In particular, the method allows a significant simplification of the system technology and the attendant cost savings, since the housing shell can be produced on the winding machine by continuing the winding process. A separate assembly line for inserting the winding into the housing and for assembling the housing can be dispensed with.

[0163] Two variants of the method according to the invention are particularly preferred. In a first variant, the method is characterized by the additional feature a. immediately below: a. After the electrode-separator assembly is fabricated to form a housing shell of the energy storage cell, the housing shell is formed with one end section of the current collector.

[0164] This end section of the ribbon current collector is not coated with electrode material.

[0165] In a second variant, the method is characterized by the additional feature b. immediately below: b. After the electrode-separator assembly is manufactured, a separate foil, particularly a separate metal foil, is wound onto the wound shell of the electrode-separator assembly to form a housing shell of the energy storage cell.

[0166] For further details of the method and of the energy storage cell which can be produced using the method, reference is made to the above description of a preferred embodiment of the energy storage cell according to the invention.

[0167] In a preferred embodiment, the method according to the invention comprises the following additional features: a. After winding at least two layers of foil, in particular metal foil, and forming a housing shell on the wound shell of the electrode-separator assembly, the formed housing shell is welded, in particular laser welded, to the edge region of the housing end face.

[0168] A liquid-tightly sealed housing can be produced in a particularly advantageous manner by welding a housing shell formed by a metal foil layer to the edge region of the housing end face. Such welding is widely used in the area from the assembly of energy storage cells and can be carried out very accurately and precisely and also in an automated manner.

[0169] As mentioned above, depending on the specific realization of the housing end face, which may in particular be realized in the form of a metal disk or cap or a combination of a cap and a contact element or a combination of a disk and a contact element, the welding may start in different areas. For example, the metal foil layer forming the housing shell can be wrapped from the outside to cover the peripheral side wall of the metal cap forming the end face of the housing. In this case, the housing shell can be joined and sealed to the cap by laser welding through the entire material thickness.

[0170] In another embodiment, the foil layers, in particular the metal foil layers, forming the housing shell can be wound so that the edge areas of the spirally wound foil ribbon are flush. Within this flush finish, welding can be performed, for example by laser welding at the seams, to metal disks or metal caps on the end faces of the housing.

[0171] With regard to the welding of the housing shell rolled from foil to the housing end face, the method according to the invention is particularly preferably characterized by at least one of the following additional features: a. the welding is performed by laser welding; b. the welding is performed such that the laser beam first penetrates the side wall of the metal cap before it strikes the foil layer of the housing shell; c. at least one of the end faces of the housing is formed by a metal cap having a peripheral recess as described above, bounded on the outside by a side wall of the cap;

[0172] Preferably, the above-mentioned features a. and b. and particularly preferably the above-mentioned features a. to c. are realised in combination with one another.

[0173] The peripheral recess of the metal cap according to feature c. above has an outer first recess side (the inner side of the cap's sidewall) and an inner second recess side bounding the peripheral recess on either side thereof.

[0174] The peripheral recess in the metal cap provides a very advantageous way of applying a welding beam, in particular a laser beam, so that the welding beam penetrates the side wall of the end cap and welds the foil layer forming the housing shell to the peripheral side wall of the cap. This type of welding, starting from the hard metal material of the end element and welding the foil layer starting from the hard metal material, has proven to be particularly advantageous.

[0175] In a preferred embodiment of the method according to the invention, at least one of the following additional features a. and b. is provided: a. the first and / or second housing end faces of the energy storage cell are formed by a circular metal disk or metal cap including a circular bottom and a peripheral side wall, and after winding of the electrode-separator assembly and before the housing shell of the energy storage cell is formed, the first and / or second wound body end faces are welded to the circular metal disk or metal cap; b. To form the first and / or second housing end faces of the energy storage cell, before the housing shell of the energy storage cell is formed, at least one contact element, optionally including a separate electrical conductor fixed to the contact element, is welded to the first and / or second winding end faces, the contact element preferably being electrically insulated from the metal disc or cap forming the first housing end face or the metal disc or cap forming the second housing end face.

[0176] Preferably, the above mentioned features a. and b. are realised in combination with each other, so that on one side of the energy storage cell, one winding end face is preferably in direct contact with a metal disk or cap forming the housing end face, while on the other side, in addition to the metal disk or cap forming the housing end face, a contact element is provided to which the corresponding winding end face is connected.

[0177] To simplify the contact of the winding end faces with the metal disk or metal cap or contact element, in preferred embodiments the following additional features are provided: a. Prior to welding the winding end faces of the electrode-separator assembly to the round, in particular circular, metal disk and / or metal cap and / or contact element, edge regions of the current collector that may protrude from the winding end faces on each side of the electrode-separator assembly and that do not contain electrode material are bent in the direction of the central axis of the electrode-separator assembly.

[0178] As already explained above in connection with the energy storage cell according to the invention, it may be provided that the metal disks or metal caps forming the end faces of the housing or, where applicable, the contact elements have an aperture or recess, which may be used during assembly of the energy storage cell according to the invention to introduce electrolyte liquid into the interior of the energy storage cell so as to impregnate it with the electrode-separator assembly. The aperture or recess may then be closed, for example, by means of a blind rivet.

[0179] Advantageously, the method for manufacturing an energy storage cell according to the invention also uses at least one insulating means for preventing short circuits between the electrodes of the cell, preferably arranged between the contact elements and a metal disk or cap forming each housing end face of the cell.

[0180] For further details on this insulating means, see the above description. In particular, the insulating means can be arranged after the winding end faces have been connected with metal disks or caps forming the housing ends or, if necessary, contact elements, before the foil layer is wound to form the housing shell.

[0181] For example, an annular insulating material or insulating tape bonded to the edge of the winding in the region of the end face of the housing to be insulated is suitable for this purpose.

[0182] In a particularly preferred embodiment of the method according to the invention, the foil layers, in particular the metal foil layers, which form the housing shell are bonded together during the method. For this purpose, the metal foil ribbon or the corresponding sections of the metal foil ribbon provided to form the housing shell can be provided beforehand with an adhesive layer, which can be sprayed or squeezed, for example. This can be a liquid adhesive, a hot melt adhesive or a thermoplastic adhesive. If a thermoplastic adhesive is used, the housing shell can then be sealed, in particular by curing the adhesive. With regard to the adhesive, reference is also made to the above explanations regarding the energy storage cell according to the invention.

[0183] Further features and advantages of the invention are set forth in the following description of examples in conjunction with the drawings. The individual features can be realized individually or in combination with one another. [Brief description of the drawings]

[0184] [Figure 1] FIG. 1 is a longitudinal section through an energy storage cell according to the present invention. [Diagram 2] FIG. 2 is a longitudinal section through a further embodiment of an energy storage cell according to the invention. [Diagram 3] FIG. 2 is a schematic diagram of the components of an electrode-separator assembly. [Figure 4] FIG. 2 is a schematic diagram of an electrode-separator assembly with a housing shell of an energy storage cell according to the present invention in a top view. [Diagram 5] 3A to 3C are schematic longitudinal cross-sectional views of further embodiments of an energy storage cell according to the present invention; [Figure 6] 2 is a schematic longitudinal section through a further embodiment of an energy storage cell according to the invention; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0185] 1 shows a preferred embodiment of an energy storage cell 100 according to the present invention. At the center of the cell are electrode ribbons 105, 108 and an electrode-separator assembly 104 in the form of ribbon separator windings. For clarity of presentation, the ribbon separator is not shown here.

[0186] An electrode-separator assembly 104 in the form of a winding is arranged axially within the energy storage cell 100. The electrode-separator assembly 104 comprises a first winding end face 120 and a second winding end face 130. The first winding end face 120 is arranged in the area of ​​a first housing end face 140. The second winding end face 130 is arranged in the area of ​​a second housing end face 150. For example, the negative pole of the cell is arranged in the area of ​​the first housing end face 140 and, correspondingly, the positive pole of the cell is arranged in the area of ​​the second housing end face 150.

[0187] The electrode-separator assembly 104 is formed such that the electrode ribbons 105, 108 each have a longitudinal edge that is not coated with electrode material. These free longitudinal edges of the electrode ribbons 105, 108 protrude from the electrode-separator assembly 104 at the opposite winding end faces 120, 130, respectively. In the example shown here, the uncoated edge of the anode current collector of the negative electrode 105 protrudes from the first winding end face 120. The uncoated edge of the cathode current collector of the positive electrode 108 protrudes from the second winding end face 130. Electrical contact of the electrodes occurs via these edge regions of the current collectors. For this purpose, a metal cap 160 provided with a peripheral side wall 161 is provided on the second winding end face 130. The metal cap 160 is provided with a plurality of beads 162 that facilitate electrical contact with the cathode current collector by welding. The metal cap 160 also forms the second end 150 of the housing.

[0188] A metal contact element 170 in the form of a metal disk with several beads 171 is arranged in the region of the first winding end 120. Here too, electrical contact is made with the edge area of ​​the anode current collector, which is free of electrode material, by means of welding. The first housing end 140 is formed on this side by a metal cap 180 with a peripheral side wall 181. In the center of the metal cap 180 there is a pole bushing 190 in which a pole stud 191 is guided, electrically insulated from the metal cap 180 by insulating means 192, for example an insulating ring. The pole stud 191 is in electrical contact with the contact element 170, so that the anode potential is conducted to the outside via the pole stud 191.

[0189] Insulating means 193, for example a peripheral insulating ring or a peripheral insulating tape, are arranged between the contact element 170 and the upper edge of the electrode-separator assembly on this side of the cell, on the one hand, and the metal cap 180 on the other hand.

[0190] In accordance with the present invention, the housing shell 200 of the energy storage cell 100 in this embodiment is formed by a multi-layer metal foil wound onto the electrode-separator assembly 104. In this exemplary embodiment, the metal foil forming the housing shell 200 forms the cathode current collector of the positive electrode 108 and is a continuous winding of a metal foil ribbon that is not coated with an electrode material.

[0191] To produce the housing shell 200, the electrode-separator assembly 104 is first wound on a winding machine in a manner known per se. A ribbon-like separator is provided between each of the electrode ribbons. When viewed from the inside to the outside, first one electrode ribbon runs out, and then the coating of the other electrode ribbon runs out at the same time or with some delay, whereby the ribbon-like separator and the current collector of the other electrode ribbon continue. After, for example, two further turns, the ribbon-like electrode-separator assembly also ends, thus forming the end of the winding of the electrode-separator assembly. However, the current collector of the other electrode ribbon remains.

[0192] Then, on both sides of the electrode-separator assembly, the winding end contacts with metal caps or metal disks or contact elements are made. For this purpose, for example, cuts are made in the remaining current collector ribbon to make it easier to fit the metal cap 160. To improve the accuracy of the fit when the cap 160 and the contact element 170 are joined, the free edge areas of the spirally wound current collector, which protrude from the electrode-separator assembly on both winding end faces, can be pre-bent towards the centre of the winding. After welding on the cap 160 and the contact element 170, the winding of the remaining current collector ribbon continues, whereby these metal foil layers form the housing shell 200.

[0193] In the example shown in FIG. 1, the cathode current collector ribbon or metal foil forming the housing shell 200 is wound so that the metal foil rests on the outside of the peripheral side wall 161 of the metal cap 160 in the region of the second housing end 150. In the region of the first housing end 140, the edges of the metal foil forming the housing shell 200 close flush so that the metal cap 180, with its peripheral side wall 181, can sit on this flush closure of the edges of the metal foil forming the housing shell 200. In the region of the second housing end 150, the metal foil layers forming the housing shell 200 are fixed and sealed by laser welding over the entire material thickness. In the region of the first housing end 140, laser welding is performed at the seam between the flush edge of the housing shell 200 and the opening edge of the side wall 181 of the cap 180. The arrows in FIG. 1 indicate the welded joint points.

[0194] In a preferred embodiment of the energy storage cell 100, the metal cap 160 on the second end face 150 may be formed of aluminum or an aluminum alloy. The cathode current collector is also preferably formed of aluminum or an aluminum alloy. The contact element 170 on the first end face 140 is preferably formed of copper or a copper alloy. The anode current collector is also preferably formed of copper or a copper alloy.

[0195] Figure 2 shows a further embodiment of an energy storage cell 300 according to the invention, which is mainly equivalent to the embodiment of the energy storage cell 100 of figure 1. Corresponding elements have therefore been given the same reference signs and reference is made in this regard to the description of figure 1.

[0196] In contrast to the embodiment of FIG. 1, the housing shell 200 of the energy storage cell 300 is not formed by a continuous current collector ribbon, but rather by a separate metal foil wound onto the electrode-separator assembly 104.

[0197] In the embodiment shown in Fig. 2, the metal foil forming the housing shell 200 has a width slightly larger than the electrode ribbons and ribbon-like separators forming the electrode-separator assembly 104. The wound housing shell 200 therefore projects somewhat further beyond the first winding end face 120 to which the contact element 170 is welded in the region of the first housing end face 140 than in the embodiment shown in Fig. 1. Correspondingly, the first end face 140 of the energy storage cell 300 is terminated by a metal disk 280. To connect the metal disk 280 to the edge of the wound housing shell 200, a laser weld can be performed from above in the corresponding edge side region, as indicated by the arrows.

[0198] In the region of the second housing end 150, the metal foil layers forming the housing shell 200 are joined and sealed by laser welding over the entire material thickness of the housing shell 200, similar to the embodiment of the energy storage cell 100 in FIG.

[0199] 3, a preferred structure of an electrode-separator assembly 104 is shown. The assembly 104 comprises a ribbon-shaped anode 105 having a ribbon-shaped anode current collector 106 with a first longitudinal edge 106a and a parallel second longitudinal edge. The anode current collector 106 is, for example, a copper or nickel foil. It comprises a strip-shaped main area loaded with a layer of anode material 107 and a free edge strip 106b extending along its first longitudinal edge 106a and not loaded with electrode material 107.

[0200] Furthermore, the ribbon electrode-separator assembly 104 comprises a ribbon cathode 108 having a ribbon cathode current collector 109 with a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is in particular an aluminum foil. It comprises a strip-shaped main area loaded with a layer of positive electrode material 110 and a free edge strip 109b extending along its first longitudinal edge 109a and not loaded with electrode material 110. Both electrodes are shown individually in an unwound state.

[0201] The anode 105 and the cathode 108 are offset from one another within the electrode-separator assembly 104 such that a first longitudinal edge 106a of the anode current collector 106 protrudes from a first terminal end face 104a and a first longitudinal edge 109a of the cathode current collector 109 protrudes from a second terminal end face 104b of the electrode-separator assembly 104. The offset arrangement can be seen in the bottom left view. Two ribbon-like separators 116 and 117 that separate the electrodes 105 and 108 from one another within the winding are also shown there.

[0202] In the bottom right figure, the electrode-separator assembly 104 is shown in a wound form as it may be used in an energy storage cell according to Figure 1 or 2 or in an energy storage cell according to Figures 5A-C described below. The electrode edges 106a and 109a protruding from the end faces 104a and 104b are clearly visible. The wound body shell 104c is formed, for example, by several turns of ribbon-like separators 116, 117 or for example plastic foils.

[0203] Such an electrode-separator assembly 104 in the form of a winding is conveniently fabricated on a winding machine. To facilitate contact with the components of the energy storage cell on the winding end faces, the non-coated edge regions of the electrode ribbons 105, 108 are preferably arranged in particular towards the winding core.

[0204] The metal disks or metal caps 160 or contact elements 170, with which the contact with the electrodes 105, 108 is made, are preferably welded onto the winding end faces on the winding machine. This can be done in particular in the region of beads 162, 171 which are advantageously present on these elements, i.e. on the metal disks or metal caps or contact elements.

[0205] Advantageously, these components on the winding end have a central opening that can be used to guide these elements over the winding needle during positioning in the winding machine, which can also be used to inject the electrolyte.

[0206] In the case of a metal cap with a peripheral side wall, the cap is advantageously positioned so that the height of the peripheral side wall is slightly less than the width of the non-coated area of ​​the respective electrode ribbon. The diameter of the peripheral side wall is equivalent to the diameter of the winding. The height of the side wall is equivalent to the non-coated area of ​​the electrode. The height of the side wall may be, for example, 1.5 to 2.5 mm.

[0207] The beads 162 of the metal caps 160 or the beads 171 of the contact elements 170 may be arranged in a star shape, for example three beads per cap 160 or per contact element 170. In the center of the caps 160 or contact elements 170 there may be an aperture or hole that can be used to pass the winding needle and thus position these elements on the winding end faces.

[0208] FIG. 4 shows the structure of the electrode-separator assembly 104 around which the housing shell is wound as a cross-sectional view of an energy storage cell 100, 300 according to the invention. In the center of the spiral structure, the winding starts with a first ribbon-like separator 117, a first electrode ribbon, e.g., a negative ribbon 105, a second ribbon-like separator 116 and a second electrode ribbon, e.g., a positive ribbon 108. After several turns, the negative ribbon 105 ends first. Approximately in the same area, the electrode material coating of the positive ribbon 108 ends, and the non-coated cathode current collector 109 and the ribbon-like separators 116 and 117 continue for several turns. Then, the ribbon-like separators 116 and 117 also end, so that only the cathode current collector 109 continues for several turns. Only these last turns of the cathode current collector 109 form the housing shell 200. In this embodiment, the housing shell 200 is therefore formed by aluminum foil, provided that the cathode current collector 109 is aluminum foil.

[0209] Similarly, an anode current collector made, for example, of copper foil, can be used to form the housing shell.

[0210] In other embodiments, a separate foil, which may be a metal foil or a plastic foil or a combination of both, may be used to form the housing shell 200. When manufacturing the housing shell 200, the metal foil may therefore come directly from the electrode winding as an uncoated current collector or be provided separately in the winding machine, so that it is either directly connected to the electrode potential or already insulated.

[0211] The foil for forming the housing shell 200, in particular the metal foil for forming the housing shell 200, can be wound to have equal or unequal thicknesses up to the maximum outer diameter of the energy storage cell. This foil forms the actual outer surface of the cell housing and replaces the housing cup provided in conventional energy storage cells.

[0212] Advantageously, the winding machine can control the position of overlap of the electrode ribbon and the ribbon-like separator. This allows the foil, especially the metal foil, to be moved further towards the centre when forming the end-face housing shell. In this way, different constructions of the housing shell 200 are possible. For example, when the housing shell 200 is formed exclusively from an aluminium foil, especially by continuing the cathode current collector, the foil material can be moved back and forward between the anode side and the cathode side so that the end-side regions of the housing shell are formed thinner. Correspondingly, the housing shell can be formed with a copper foil, which is used as a continuous section of the anode current collector, especially for the winding of the housing shell.

[0213] In other embodiments, the housing shell may be formed of different foils, for example different metal foils, for example aluminum foil and copper foil.

[0214] If necessary, for example if a wider foil needs to be tapered at an end, the current collector foil can be cut to shape in the machine or in an upstream machine. The current collector foil or another foil forming the housing shell can be cut, for example, using a laser, a punch or a shear cut.

[0215] During the winding of the foil forming the housing shell, the first or, if applicable, all layers may be welded to an element forming the housing end face, ie in particular a metal cap or a metal disk.

[0216] These methods are used to form a wound body having a fixed outer surface and housing end termini. The electrolyte can be injected through any holes or apertures in the end elements of the housing that are also used for the winding needles. The apertures or holes can later be closed using, for example, blind rivets.

[0217] Particularly advantageously, the winding layers forming the housing shell 200 are glued, which ensures the robustness of the housing shell. A standard adhesive, for example a liquid adhesive, can be used for this purpose. Alternatively, for example a plastic can be encapsulated. The corresponding section of the foil ribbon can be pre-coated for such a seal. For example, if the housing shell 200 is formed by an end section of a current collector of an electrode ribbon, this end section, for example the last few centimeters of the current collector ribbon, can be directly coated with a thermoplastic material, so that a seal can later be made on this thermoplastic material.

[0218] Conventional energy storage cells with a 21700 form factor generally have a housing wall thickness of 0.25 mm and are made, for example, of nickel-plated steel. To insert the electrode-separator assembly or the electrode winding into the housing cup, a clearance of about 0.2 mm in diameter is required that remains unused for the electrode material. In the energy storage cell according to the invention with a wound housing shell, this unused space can be fully utilized. In order to achieve a great stability of the housing shell in the cell according to the invention, the wall thickness of the foil layer forming the housing shell can even be greater than the usual wall thickness of 0.25 mm in conventional cells, without a decrease in the capacity of the resulting cell. For example, the wall thickness of the energy storage cell according to the invention can be up to 0.35 mm, formed, for example, by 20 layers of aluminum foil, without an increase in the diameter of the cell and without a decrease in capacity compared to conventional energy storage cells.

[0219] The assembly of conventional energy storage cells, including the upstream fabrication of the electrode-separator assembly and the cell assembly with the housing cup, usually accounts for about one third of the total fabrication cost, of which about one third is due to the fabrication of the electrode-separator assembly. The fabrication of the energy storage cells according to the invention eliminates the line for cell assembly, and therefore the fabrication cost can be significantly reduced, even if the winding process must be adapted to form the housing shell with the foil according to the invention.

[0220] As an alternative to the direct contact of the electrode ribbons via the flat end elements of the energy storage cells shown in Figures 1 and 2, i.e. in particular directly via metal disks or caps on the end faces of the housing or directly via flat contact elements (contact plate design), a metallic contact strip can also be used for contacting the electrodes in a manner known per se. It is particularly preferred if one of the electrodes, for example the cathode, is contacted via a flat contact of the spiral edge of the uncoated cathode current collector protruding from the respective winding end face, and the anode side of the electrode-separator assembly is contacted via a metallic contact strip. In particular, this contact strip can be welded perpendicular to the direction of travel of the corresponding electrode strip on the free section of the strip-like current collector that is not loaded with electrode material and protruding from the winding on the corresponding winding end face, and used for contacting.

[0221] The size or form factor of the energy storage cell according to the invention is in principle not limited. The height of the energy storage cell according to the invention, which is preferably designed as a cylindrical round cell, is in the range of 50 mm to 150 mm. Its diameter is preferably in the range of 15 mm to 60 mm. Cylindrical round cells with these form factors are particularly suitable for supplying power to electric drives in motor vehicles. However, smaller cylindrical round cells or button cells, for example, can also be easily manufactured according to the principles of the invention.

[0222] In addition to metal foils, other ribbon-shaped substrates such as metal or metallized nonwovens or open-pore metal foams or expanded metals can in principle also be used as current collectors, although in this case the preferred embodiment of the cell described above, in which the housing shell is formed by one end section of the current collector, is generally not suitable, but the embodiment in which the housing shell is formed by a separate foil can easily be realised with such other ribbon-shaped substrates.

[0223] Figure 5 shows in partial views A, B and C further possible embodiments 400, 500 and 600 of an energy storage cell according to the invention. The energy storage cells 400, 500, 600 each comprise a wound electrode-separator assembly 104. In contrast to the embodiments of the energy storage cell according to the invention shown with reference to figures 1 and 2, the housing shell 200 of the energy storage cells 400, 500 and 600 is at least partially formed by a plastic foil.

[0224] In the energy storage cell 400 shown in FIG. 5A, the electrical connection of the electrodes of the electrode-separator assembly 104 is realized by two metal caps 460 arranged on each end face of the energy storage cell 400. After completion of the wound electrode-separator assembly 104, these metal caps 460 are electrically connected, in particular welded, to the current collector ribbons of the electrodes that form each end face of the winding. Next, a number of plastic foil layers 210 are wound around the outer periphery of the electrode-separator assembly 104 to form the housing shell 200. The housing can be sealed by welding the plastic foil layers 210 to the end caps 460.

[0225] 5B shows a further embodiment of an energy storage cell 500 according to the invention. Here, the end faces of the electrode-separator assembly 104 are electrically contacted with metal components 560, which each cover an end face of the electrode-separator assembly and at the same time form a pole pin 570. The housing shell 200 is formed by a plastic foil layer 210 wrapped around the exterior of the electrode-separator assembly 104. In either case, a plastic seal 580 or a corresponding perforated plastic disk, which seals the end face of the energy storage cell 500 flush with the exterior, may be provided around the respective pole pin 570.

[0226] The embodiment of the energy storage cell 600 shown in FIG. 5C has a housing shell 200 formed by several layers of metal foil 220 in the inner region and several layers of plastic foil 210 in the outer region. For the electrical contact of the electrodes, a metal cap 650 is provided in this embodiment on the lower end face of the electrode-separator assembly 104, and a metal component 660 with an integrally formed pole pin 670 is provided on the upper end face of the electrode-separator assembly 104. A peripheral insulating element 680, in particular a plastic enclosure, surrounds both the outer edge of the metal component 660 and its upper edge within a certain range from its end face of the electrode-separator assembly in order to electrically insulate the metal component 660 from the other components of the energy storage cell 600. At the same time, the insulating element 680 flushly closes the upper end face of the energy storage cell 600.

[0227] Figure 6 shows a further particularly advantageous embodiment of an energy storage cell 700 according to the invention. The energy storage cell 700 is substantially similar to the embodiment of the energy storage cell 300 shown in Figure 2. Therefore, for most of the features described above, reference is made to the description of Figure 2.

[0228] Compared to the embodiment of the energy storage cell 300 according to Fig. 2, the end face 150 of the energy storage cell 700, which forms the positive pole of the cell, has a slightly different design: the metal cap 160 has in its edge region a peripheral recess bounded on the outside by the side wall 165 of the cap 150 and on the inside by a beveled wall 166. The boundary walls 165, 166 form a sort of channel or groove in the outer edge region of the metal cap 160. This cavity formed here can be used to position a laser beam, indicated by two oblique arrows, so that the foil layers forming the housing shell 200 are welded through the side wall 165. This procedure for welding the housing shell 200 to the end face of the cell has proven to be particularly advantageous and practical.

Claims

1. An energy storage cell (100, 300, 400, 500, 600, 700) having a cylindrical housing that is liquid-tight closed and has a first housing end face (140) and a second housing end face (150) and a housing shell (200), the energy storage cell having the following characteristics: a. said cylindrical energy storage cell (100, 300, 400, 500, 600, 700) includes an electrode-separator assembly (104) disposed within said housing; b. the electrode-separator assembly (104) is in the form of a cylindrical winding formed of an electrode ribbon (105, 108) and at least one ribbon-like separator (116, 117), the winding having first and second terminal winding end faces (120, 130) and a winding shell; c) said electrode-separator assembly (104) is axially disposed within said housing such that said first winding end face (120) faces toward said first housing end face (140) and said second winding end face (130) faces toward said second housing end face (150); and has the following features: d. The housing shell (200) of the energy storage cell is formed of at least one spirally wound foil, preferably a spirally wound metal foil, and includes at least two layers of said foil, preferably said metal foil. An energy storage cell characterized by (100, 300, 400, 500, 600, 700).

2. Additional features include: a. the electrode-separator assembly (104) comprises a positive electrode ribbon (108) having a first longitudinal edge and a parallel second longitudinal edge, the positive electrode ribbon (108) comprising a ribbon-shaped cathode current collector (109) coated on both sides with a positive electrode material (110); b. the electrode-separator assembly (104) comprises a negative electrode ribbon (105) having a first longitudinal edge and a parallel second longitudinal edge, the negative electrode ribbon (105) comprising a ribbon-shaped cathode current collector (106) coated on both sides with a negative electrode material (107); c. the at least one ribbon separator (116, 117) electrically insulates the opposite polarity electrode ribbons (105, 108) from each other; 10. The energy storage cell of claim 1, comprising at least one of:

3. Additional features include: a. the spirally wound foil forming the housing shell (200) of the energy storage cell is a spirally wound end section of the ribbon-shaped cathode current collector (109) that is not coated with the positive electrode material; b. the spirally wound foil forming the housing shell (200) of the energy storage cell is a spirally wound end section of the ribbon-shaped anode current collector (106) that is not coated with the negative electrode material; c. the ribbon-shaped cathode current collector (109) and the ribbon-shaped anode current collector (106) have an essentially constant width along their entire length; 3. The energy storage cell of claim 2, comprising at least one of:

4. Additional features include: a. the spiral wound foil forming the housing shell (200) of the energy storage cell is a spiral wound foil ribbon wound onto the winding shell of the electrode-separator assembly (104); b. the winding shell of the electrode-separator assembly (104) is formed of an electrically insulating material; c) the foil ribbon, in particular the metal foil ribbon, has an essentially constant width over its entire length; d. said foil ribbon, in particular said metal foil ribbon, having a width greater than said ribbon-shaped cathode current collector (109) and / or said ribbon-shaped anode current collector (106) of said electrode-separator assembly (104); 3. The energy storage cell according to claim 1, further comprising at least one of:

5. Additional features include: a. the spirally wound foil forming the housing shell (200) of the energy storage cell is made of aluminum or an aluminum alloy; b. the spirally wound foil forming the housing shell (200) of the energy storage cell is made of copper or nickel or a copper or nickel alloy; c. The spirally wound foil forming the housing shell (200) of the energy storage cell is made of plastic. The energy storage cell according to any one of claims 1 to 4, comprising any one of:

6. Additional features include: a. the foil layers, in particular the metal foil layers, forming the housing shell (200) of the energy storage cell are joined together by adhesive layers arranged between the layers; The energy storage cell according to any one of claims 1 to 5, having

7. Additional features include: a. at least one of said ribbon-shaped current collectors has at least one free section that is not coated with said electrode material and to which a metal contact strip is welded; b. The metal contact strip welded to the current collector protrudes from one of the winding end faces. The energy storage cell according to any one of claims 1 to 6, comprising at least one of:

8. Additional features include: a. the first housing end (140) of the energy storage cell is formed of a round, in particular circular, metal disk (280) or a metal cap (180) including a round, in particular circular, bottom and a peripheral side wall (181); b. the metal disk (280) or cap (180) forming the first housing end face is connected to the housing shell (200) by welding; c) the second housing end (150) of the energy storage cell is formed by a round, in particular circular, metal disk or metal cap (160) including a round, in particular circular, bottom and a peripheral side wall (161); d. The metal disk or cap (160) forming the second housing end face is connected to the housing shell (200) by welding. The energy storage cell according to any one of claims 1 to 7, comprising at least one of:

9. Additional features include: a. the metal contact strip welded to the current collector is connected, preferably by welding, directly to the metal disk or cap forming the first end face of the housing or to the metal disk or cap forming the second end face of the housing; 9. The energy storage cell of claim 8 in combination with claim 7,

10. Additional features include: an electrical contact pole (191) is led through said first housing end face and / or said second housing end face (140, 150), said contact pole (191) being electrically insulated from said respective housing end face and electrically connected to one of said ribbon-shaped current collectors (106, 109) directly or via a metallic conductor; b. one of said ribbon-shaped current collectors (106, 109) is electrically connected, either directly or via a metal conductor, to said metal disk or cap forming said first housing end face (140) or to said metal disk or cap (160) forming said second housing end face (150); 10. The energy storage cell of claim 8 or 9, comprising at least one of:

11. Additional features include: said ribbon-shaped current collector (106) comprising a main area loaded with a layer of said negative electrode material (107) and a free edge strip (106b) extending along a first longitudinal edge (106a) thereof and not loaded with said negative electrode material; b. said ribbon-shaped cathode current collector (109) comprises a main area loaded with a layer of cathode material (110) and a free edge strip (109b) extending along its first longitudinal edge (109a) that is not loaded with said cathode material; c. The electrode ribbons (105, 108) are - said first longitudinal edge (106a) of said anode current collector or said first longitudinal edge (109a) of said cathode current collector protrudes from one of said end winding end faces, or - the first longitudinal edge (109a) of the cathode current collector projects from one end winding end face of the electrode-separator assembly, and the first longitudinal edge (106a) of the anode current collector projects from the other end winding end face; In this way, the electrode-separator assembly (104) is formed as a winding. The energy storage cell according to any one of claims 2 to 10, comprising at least one of:

12. Additional features include: a. one of said ribbon-shaped current collectors (106, 109) is directly electrically connected to said metal disk or cap forming said first housing end face (140) or to said metal disk or cap forming said second housing end face (150), said first longitudinal edge of said respective current collector resting directly on said bottom of said metal disk or cap and connected thereto, preferably by welding over its entire length; 12. The energy storage cell of claim 11 in combination with claim 8,

13. Additional features include: a. the first longitudinal edge (106a) of the anode current collector and / or the first longitudinal edge (109a) of the cathode current collector protrudes from one of the end winding end faces and has a spiral shape; b. at least an outer turn of said first longitudinal edge is bent toward a central axis of said electrode-separator assembly (104); 13. The energy storage cell of claim 11 or 12, comprising at least one of:

14. Additional features include: said energy storage cell comprises at least one contact element (170), optionally comprising a separate electrical conductor fixed thereto, connected, preferably by welding over its entire length, to said first longitudinal edge of said cathode current collector (109) or said anode current collector (106), via said at least one contact element (170) said current collector is electrically connected to said metal disk or cap forming said first housing end face (140) or to said metal disk or cap forming said second housing end face; b. the contact element (170) seats flat on the first longitudinal edge of the cathode current collector or the anode current collector; c) the contact elements include a first element seated flat on the first longitudinal edge of the current collector projecting from the first or second end face and extending parallel to the respective winding end face, and a second element adjacent the first element at an angle thereto, through which the first element is electrically connected to the metal disk or cap forming the first housing end face or the metal disk or cap forming the second housing end face; d) the contact elements are directly connected, in particular by welding, to the metal disk or cap forming the first housing end face or to the metal disk or cap forming the second housing end face; e. The contact element (170) makes contact directly or via an electric conductor with an electric contact pole (191) passing through the first housing end surface and / or the second housing end surface. The energy storage cell according to any one of claims 2 to 13 in combination with claim 8, comprising at least one of:

15. Additional features include: a. the metal cap forming at least one of the end faces of the housing has in its edge region a peripheral recess, in particular an annular recess, bounded on the outside by the peripheral side wall of the metal cap; b. the peripheral side wall of the metal cap lies flat against the foil forming the housing shell; The energy storage cell (700) of any one of claims 8 to 14, comprising at least one of:

16. A method for manufacturing an energy storage cell (100, 300, 400, 500, 600, 700) having a cylindrical, liquid-tight sealed housing having a first housing end face (140) and a second housing end face (150) and a housing shell (200) according to any one of claims 1 to 15, comprising: a. an electrode-separator assembly (104) in the form of a winding having two terminal winding end faces and a winding shell is fabricated on a winding machine, said electrode-separator assembly being formed of electrode ribbons (105, 108) between which at least one ribbon-like separator (116, 117) is disposed, said electrode ribbons each preferably comprising a ribbon-like current collector coated with an electrode material; b. said housing shell (200) is formed by winding a foil, in particular a metal foil; The method includes:

17. Additional features include: a. The housing shell (200) formed of wound foil is welded to at least one of the housing ends (140, 150).

17. The method of claim 16, comprising:

18. Additional features include: a. the welding is performed by laser welding; b. welding is performed such that a laser beam first penetrates the side wall of the metal cap before it strikes the foil layer of the housing shell; c) at least one of said end faces of said housing is formed by a metal cap having a peripheral recess as described above, bounded on its outer side by a sidewall of said cap; The method of claim 17, comprising at least one of the following:

Images